Question

What is the molar solubility of magnesium carbonate ( MgCO3 ) in water? The solubility-product constant for MgCO3 is 3.5 × 10-8 at 25°C.

Answer 1

Answer:

S MgCO3 = 1.8708 E-4 M at 25 °C

Explanation:

• MgCO3 ↔ Mg2+  +  CO32-

           S                S             S

• Ksp = 3.5 E-8

⇒ Ksp = 3.5 E-8 = [ Mg2+ ] * [ CO32- ] = S * S

⇒ Ksp = 3.5 E-8 = S²

⇒ S = √3.5 E-8

⇒ S = 1.8708 E-4 M

   

Answer 2

Answer:

1.75 ×10^-8 moldm-3

Explanation:

MgCO3(s) <----------> Mg^2+(aq) + CO3^2-(aq)

Ksp= 2x

x= Ksp/2

But Ksp= 3.5 × 10^-8 mol^2dm^-6

x= 3.5 × 10^-8/2

x= 1.75 ×10^-8 moldm-3